Vehicle steer axle assembly

ABSTRACT

In one aspect, a vehicle steer axle has a horizontal axle member that has a steering axis male feature integrally formed on an end, wherein a vehicle steering knuckle, which forms a vehicle steering axis female feature, is directly rotatably coupled to the vehicle steer axle. In another aspect, a vehicle steering knuckle has a horizontal steering knuckle member that has a steering axis male feature integrally formed on an end, wherein the vehicle steering knuckle is directly rotatably coupled to a vehicle steer axle, which forms a vehicle steering axis female feature. Neither of these aspects utilize a separable kingpin.

RELATED APPLICATIONS

This application is a divisional application of and claims benefit,under 35 U.S.C.§120, of pending U.S. patent application Ser. No.11/650,682, filed Jan. 8, 2007, which application is incorporated byreference herein in its entirety.

FIELD OF THE INVENTION

The present invention relates to a vehicle steer axle assembly. Moreparticularly, the present invention relates to a vehicle steer axleassembly that does not utilize a separable kingpin.

BACKGROUND OF THE INVENTION

In a conventional vehicle steer axle assembly, a steering knuckleincludes a body, steering arms, a brake mounting plate, and a spindlefor a wheel hub, bearings, and a tire assembly (see, for example, U.S.Pat. No. 6,623,019 which is incorporated herein by reference). Thesteering knuckle is coupled to a steer axle using a separable kingpinand the steering arms are connected to steering components of a vehicle.

Typically, the steering knuckle has a forked yoke that defines first andsecond bosses with aligned bores. The yoke surrounds one end of thesteer axle which defines an axle boss having an axle bore aligned withthe bores of the knuckle yoke. The kingpin extends through one or moreof the knuckle bores, through the axle bore, and through the remainingknuckle bore to rotatably couple the steering knuckle and the steer axletogether.

In these conventional steer axle assemblies, the knuckle pivots aboutthe kingpin on a vertically inclined steering axis. Typically, bushingsare disposed (for example, pressed) within the aligned bores of theknuckle to allow the knuckle to rotate relative to the kingpin.

Conventional steer axle assemblies suffer from several disadvantages.Typically, conventional steer axle assemblies allow a relatively largeamount of axial and radial movement of the knuckle relative to thekingpin, which results in the kingpin joints being subjected to addedwear. As a result, greater clearances are created, which permit thekingpin to shift and oscillate within the knuckle bores which reducesthe useful lives of the assembly components. Conventional kingpindesigns also often require manual shimming of steer axle assemblymembers in order to limit the above stated axial and radial movement ofthe knuckle relative to the kingpin. Therefore, these designs requireadditional manufacturing steps and costs. Typically, the bushings resultin relatively large tolerances and often require the operations ofbroaching or reaming of the bushings. These operations may be requiredto maintain close fit tolerances of the inside diameter of the bushingto the outside diameter of the kingpin.

Knuckles, such as those described above are complex and, thus result inhigh material, manufacturing, and labor costs. These knuckles are alsodisadvantageous since the kingpin can be difficult to remove for repairsand the kingpin itself increases the size and weight of the steer axleassembly. Further, the kingpin to steer axle joint is highly loaded and,consequently, requires a precision fit tolerance and a robust mechanismto lock the kingpin to the axle beam. The localized stress at this jointalso typically requires that high strength materials be used for thekingpin.

What is sought is to provide vehicle steer axle assemblies that do notutilize a separable kingpin, wherein the joint(s) between the steer axleand the steering knuckle is eliminated. This should at least result inproviding vehicle steer axle assemblies with lower material and laborcosts, with an elimination of endplay, with a lowering of mechanicalstress in the coupling area, and with an elimination of manual shimming.

SUMMARY OF THE INVENTION

A vehicle steer axle assembly comprising a vehicle steer axle and avehicle steering knuckle, where the vehicle steer axle or the vehiclesteering knuckle comprises a substantially horizontal member and avehicle steering axis male feature integrally formed on an end portionof the horizontal member. Wherein, the vehicle steering knuckle isdirectly rotatably coupled to the vehicle steer axle, without utilizinga separable kingpin.

Further advantages will be apparent from the following description andappended claims, reference being made to the accompanying drawingsforming a part of a specification, wherein like reference charactersdesignate corresponding parts of several views.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional and an elevational view of a first vehicle steeraxle with a first vehicle steering knuckle;

FIG. 2 is a sectional and an elevational view of a second vehicle steeraxle with a second vehicle steering knuckle;

FIG. 3 is a sectional and an elevational view of a third vehiclesteering knuckle with a third vehicle steer axle; and

FIG. 4 is a three dimensional view of a vehicle.

DETAILED DESCRIPTION OF THE INVENTION

It is to be understood that the invention may assume various alternativeorientations and step sequences, except where expressly specified to thecontrary. It is also to be understood that the specific devices andprocesses illustrated in the attached drawings, and described in thefollowing specification are simply exemplary embodiments of theinventive concepts defined in the appended claims. Hence, specificdimensions, directions or other physical characteristics relating to theembodiments disclosed are not to be considered as limiting, unless theclaims expressly state otherwise.

FIG. 1 illustrates a first vehicle steer axle assembly 10 that comprisesa first vehicle steer axle 11 and a first vehicle steering knuckle 14that includes steering arms 32, 34 that are part of the steering system(not shown). The steering arms 32, 34 are shown in FIG. 1 to be attachedto a body 40 of the first steering knuckle 14 at a position that isgenerally opposite a spindle 35 that has a top spindle shoulder 35′ anda bottom spindle shoulder 35″. The first vehicle steer axle 11 comprisesa first substantially horizontal axle member 12, which may be of aone-piece construction, that has a first vehicle steering axis malefeature 13 (that is substantially vertical) which is integrally formedon an end portion thereof and which is inclined with first steering axisSA1. By integrally formed, it is meant that the two items 12, 13 are,for example, formed by forged metal, formed by cast metal, are weldedand/or are adhesively bonded as a single member.

Although FIG. 1 illustrates the structure of a single first vehiclesteering axis male feature 13, typically, there is an essentiallyidentical first vehicle steering axis male feature 13 (i.e., a dualstructure) attached on another end portion of the horizontal steer axlemember 12 (see FIG. 4). This dual structure of similar features, whichare also discussed below, apply to other assemblies 20, 30 that areillustrated in FIGS. 2-3. All of these assemblies 10, 20, 30 may beutilized in large trucks (again see FIG. 4) or in a wide variety ofother vehicles.

The first vehicle steering knuckle 14, which forms a first vehiclesteering axis female feature 15, is directly rotatably coupled, viabearings 18, 18′, to the first vehicle steer axle 11. This rotatablecoupling is achieved without requiring a separable kingpin. The vehiclesteering axis male feature 13 extends upwardly from the horizontal steeraxle member 12 and into the vehicle steering axis female feature 15. InFIG. 1, the first vehicle steering axis male feature 13 is shown incross-section to better illustrate that there is no separable kingpin inthis assembly 10. In contrast, the first horizontal axle member 12 isnot shown in cross-section.

FIG. 1 also shows various other elements like upper bearings 18 andlower bearings 18′ (abutting their corresponding bearing raceways, thebearings 18, 18′ also apply to assemblies 20, 30), a nut 25, a spacer27, and a washer 29 (that also apply to assembly 30), which are utilizedin similar ways as those elements disclosed in U.S. Pat. No. 6,623,019.The bearings 18, 18′ may, for example, be tapered roller bearings orball bearings that are common in the art.

As a result of eliminating the kingpin, a kingpin joint(s) is eliminatedbetween the first steer axle 11 and the first steering knuckle 14. Also,as depicted in the embodiments of FIGS. 1 and 2, the tapered bearings18, 18′ are axially widely separated (when compared, for example, toU.S. Pat. No. 6,623,019) and are shown to be aligned with theircorresponding steer axes SA1-2. Specifically, the lower extremity 51 ofthe upper bearing 18 is positioned above the top spindle shoulder 35′and the upper extremity 52 of the lower bearing 18′ is positioned belowthe bottom spindle shoulder 35″.

In the first assembly 10, the nut 25 is tightened down onto the washer29 which draws the steering axis male feature 13 up within the firststeering axis female feature 15 of the first vehicle steering knuckle14, thus applying a compressive load between the washer 29 and thespacer 27.

Manual shimming is eliminated due to a small tolerance stackup betweenthe steering axis male feature 13, a bearing cone spacer 16, knucklebearing shoulders (i.e., where the cone spacer 16 internally contactsthe knuckle 14), and the bearings 18, 18′. Preloading of the firsttapered bearing 18 and the second tapered bearing 18′ is automaticallyset by the dimensions of the bearings 18, 18′ and the mating parts 13,14, 16. The preloading on the bearings 18, 18′ is significantly loweredby the wider axial separation of the bearings 18, 18′, along thesteering axis SA1. Further, as a result of the preloading of the steeraxis bearings 18, 18′, there is an elimination of endplay. Thesefeatures of the first assembly 10 apply in much the same way to thesecond and third assemblies 20, 30.

In the assemblies 10 20, 30, the inside diameter (ID) cone bore of thebearings 18,18′ is larger than conventional kingpin steer axlesassemblies. As a result, lower mechanical stress on the vehicle steeringaxis male features 13, 23, 37 is realized, thereby advantageouslyproducing steer axles 11, 21, 31 that comprise a cast metal or a forgedmetal (e.g., steel) without special heat treatment or costly metalalloys. In turn, the steer axles 11, 21, 31 would only require minimummachining.

Additional cost savings to produce the first steer axle 11 result fromits above-stated construction, since there is no separable kingpin toproduce or machine. Also, the bearings 18, 18′ are separate serviceableparts which allow the first steering knuckle 14 and the first steer axle11 to be reused. These advantages associated with the assembly 10equally apply to the assemblies 20, that are respectively illustrated inFIGS. 2 and 3 and described in more detail below.

Illustrated in FIG. 2 is a second vehicle steer axle assembly 20 thatcomprises a second steer axle 21 and a second vehicle steering knuckle24 that includes the steering arms 32, 34 that are part of the steeringsystem. The steering arms 32, 34 are shown in FIG. 2 to be attached to abody 40′ of the second steering knuckle 24 and generally positionedopposite the spindle 35 which has top/bottom spindle shoulders 35′, 35″.Although not required, the steering arms 32, 34 are shown verticallyspanning the spindle 35. The second vehicle steer axle 21 comprises asecond substantially horizontal axle member 22 (possibly of a one piececonstruction) having a second vehicle steering axis male feature 23(that is substantially vertical), which is integrally formed on an endportion of the second substantially horizontal axle member 22 and isinclined with the second steering axis SA2.

The second vehicle steering knuckle 24, which forms a second vehiclesteering axis female feature 15′, is directly rotatably coupled, via thebearings 18, 18′, to the second vehicle steer axle 21. This rotatablecoupling is achieved without requiring a separable kingpin. In FIG. 2,the second vehicle steer axle 21 is not shown in cross-section, in orderto better illustrate that there is no separable kingpin in thisembodiment 20. In contrast, the second vehicle steering knuckle 24 isshown in cross-section.

Also shown in FIG. 2 are caps 33, bolts 25′, bearings 18, 18′, and zerks39. The second vehicle steering axis male feature 23 is positionedbetween the caps 33 which are utilized in disposing the vehicle steeraxis male feature 23 within a portion of the second steering knuckle 24.The top bolts 25′ and the top cap 33 attach a top portion of the secondsteering axis female feature 15′ to a top portion of the steering axismale feature 23. This attachment may be by way of a threaded hole (notshown but common in the art) that would be defined within the secondsteering knuckle 24 or possibly threaded nuts (not shown but common inthe art) that are external to the second steering knuckle 24.

Similarly, the bottom bolts 25′ and the bottom cap 33 attach a bottomportion of the steering axis female feature 15′ to a bottom portion ofthe steering axis male feature 23. Thus, the steering axis male feature23 is attached between the steering axis female feature 15′, where thesteering axis male feature 23 may radially narrow at its top portion andat its bottom portion. The zerks 39 are utilized to provide lubricant tothe bearings 18, 18′. Manual shimming is eliminated due to a smalltolerance stackup between the knuckle 24, the steer axle male feature23, and the bearings 18, 18′.

Illustrated in FIG. 3 is a vehicle steering knuckle assembly 30 having athird vehicle steer axle 31 and a third vehicle steering knuckle 36. Thethird vehicle steering knuckle 36 comprises a substantially horizontalsteering knuckle member 38 and a third vehicle steering axis malefeature 37 that is substantially vertical. The third vehicle steeringaxis male feature 37 is integrally formed on an end portion of thehorizontal steering knuckle member 38. The third vehicle steering axismale feature 37 may radially narrow between a top portion of thesteering axis male feature 37 and a bottom portion of the steering axismale feature 37.

Wherein, the third vehicle steering knuckle 36 is directly rotatablycoupled, via the bearings 18, 18′, to the third vehicle steer axle 31that forms a third vehicle steering axis female feature 15″. Thisrotatable coupling is achieved without requiring a separable kingpin.

The third vehicle steering axis male feature 37 extends downwardly fromthe horizontal steering knuckle member 38 and into the third vehiclesteering axis female feature 15″. The third vehicle steering knuckle 36has at least one steering arm 32, 34 attached to a body 40″ of the thirdvehicle steering knuckle 36. The body 40″ may be the third vehiclesteering axis male feature 37. The horizontal steering knuckle member 38comprises a spindle 35 which may be horizontally inline with thesteering arms 32, 34, as illustrated in FIG. 3.

In the third assembly 30, the nut 25 is tightened up onto the washer 29which draws the steering axis male feature 37 down within the thirdsteering axis female feature 15″ of the third vehicle steering knuckle36 which applies a compressive load between the washer 29 and the spacer27. Manual shimming is eliminated due to a unitized construction of thebearings 18, 18′.

In FIG. 3, the third vehicle steering axis male feature 37 is shown incross-section to better illustrate that there is no separable kingpin inthis embodiment 30. To contrast, the horizontal steering knuckle member38 is not shown in cross-section.

For all three assemblies 10, 20, 30, each of the steering axes SA1-3goes through the respective axial center of the steering axis malefeature 13, 23, 37. Consequently, a steering pivot axis is formed ineach of these assemblies 10, 20, because the respective steering axismale feature 13, 23, 37 is aligned concentrically with the inside boreof the respective mating knuckle 14, 24 or the mating steer axle 31.

As an example of where the steer assemblies 10, 20, 30 could beutilized, FIG. 4 depicts a large truck 42 (commonly known as a tractoror semi-tractor) with a compartment 43. The tractor 42 is shownconnected to a trailer 44 where the tractor 42 has front wheelassemblies 45 and rear wheel assemblies 46. The trailer 44 has trailerwheel assemblies 47.

The steer assemblies 10, 20, 30 are shown as part of the front wheelassemblies where typically steering of the tractor-trailer 42, 44 takesplace. The corresponding horizontal steer axles 12, 22, 31 are shown bythe horizontal dashed line between the front wheel assemblies 45.Typically, the truck rear wheel assemblies 46 and the trailer wheelassemblies 47 are not utilized for steering, but the assemblies 10, 20,30 are not limited by the location of the steering assemblies.

It is to be understood that the patent drawings are not intended todefine precise proportions of the elements of the invention but that thepatent drawings are intended to be utilized in conjunction with the restof the specification. Unless expressly specified to the contrary, itshould also be understood that the illustrated differences betweenvarious elements, which may be in fractions of a unit of measurement,are not intended to be utilized to precisely measure those differencesbetween the various elements.

In accordance with the provisions of the patent statutes, the principlesand modes of operation of this invention have been described andillustrated in its preferred embodiments. However, it must be understoodthat the invention may be practiced otherwise than specificallyexplained and illustrated without departing from its spirit or scope.

1. A vehicle steer axle assembly, comprising: a vehicle steer axlecomprising a one piece substantially horizontal steer axle member and avehicle steering axis male feature integrally formed on an end portionthereof; a vehicle steering knuckle forming a vehicle steering axisfemale feature, said vehicle steering knuckle having at least onesteering arm and a spindle attached thereto, said spindle having a topspindle shoulder and a bottom spindle shoulder; a first tapered bearinghaving a lower extremity positioned above said top spindle shoulder; anda second tapered bearing having an upper extremity positioned below saidbottom spindle shoulder; wherein, said vehicle steering axis femalefeature is directly rotatably coupled, via said first and second taperedbearings, to said vehicle steer axle.
 2. The vehicle steer axle assemblyof claim 1, wherein said vehicle steering axis male feature extendsupwardly from said horizontal steer axle member and into said vehiclesteering axis female feature.
 3. The vehicle steer axle assembly ofclaim 1, wherein a preload of said first tapered bearing and said secondtapered bearing is automatically set by the dimensions of mating parts.4. The vehicle steer axle assembly of claim 1, further comprising a nut,a washer, and a spacer, wherein said nut is tightened down onto saidwasher to draw said steering axis male feature up within said steeringaxis female feature, thus applying a compressive force between saidwasher and said spacer.
 5. The vehicle steer axle assembly of claim 1,further comprising caps and bolts, wherein at least two of said boltsand one of said caps attach a top portion of said steering axis femalefeature to a top portion of said steering axis male feature extendingupwardly and at least two other of said bolts and another of said capsattach a bottom portion of said steering axis female feature to a bottomportion of said steering axis male feature extending downwardly, thusattaching said steering axis male feature between said steering axisfemale feature.
 6. The vehicle steer axle assembly of claim 5, furthercomprising a spindle, wherein two of said steering arms vertically spansaid spindle.
 7. The vehicle steer axle assembly of claim 1, whereinsaid steering axis male feature radially narrows at a top portion ofsaid steering axis male feature and at a bottom portion of said steeringaxis male feature.
 8. The vehicle steer axle assembly of claim 1,wherein said horizontal axle member and said vehicle steering axis malefeature are integrally formed by way of a metal forging or a metalcasting.
 9. The vehicle steer axle assembly of claim 1, wherein saidhorizontal axle member and said vehicle steering axis male feature areintegrally formed by way of welding and/or adhesive bonding.
 10. Thevehicle steer axle assembly of claim 1, further comprising a nut, aspacer, and a washer utilized to dispose said vehicle steering axis malefeature within said vehicle steering axis female feature.
 11. Thevehicle steer axle assembly of claim 1, further comprising caps, saidcaps utilized to dispose said vehicle steering axis male feature betweena top portion of said vehicle steering axis female feature and a bottomportion of said vehicle steering axis female feature.
 12. A tractorcomprising the vehicle steer axle assembly of claim 1.